Re: [Embedded-pv-devel] [Xen-devel] [PATCH RFC 05/18] xen/arm: allow reassigning of hw interrupts to guest domain

[Julien Grall <julien.grall@xxxxxxx>]

Hello,

On 18/05/16 17:32, Andrii Anisov wrote:
> From: Andrii Tseglytskyi <andrii.tseglytskyi@xxxxxxxxxxxxxxx>
>
> Patch allows reassigning of hardware interrupts from dom0 to
> other guest domain.
Can you explain why route_irq_to_guest should  be able to cope with 
reassigning an IRQ rather than having dom0 calling 
XEN_DOMCTL_unbind_pt_irq beforehand?
Also, this patch does more than allowing an IRQ to be reassigned from 
DOM0 to DOMU, it also allows DOMU to DOMU.
Regards,

> Signed-off-by: Andrii Tseglytskyi <andrii.tseglytskyi@xxxxxxxxxxxxxxx>
> Signed-off-by: Iurii Konovalenko <iurii.konovalenko@xxxxxxxxxxxxxxx>
> ---
>   xen/arch/arm/irq.c | 19 +++++++++++++++----
>   1 file changed, 15 insertions(+), 4 deletions(-)
>
> diff --git a/xen/arch/arm/irq.c b/xen/arch/arm/irq.c
> index 1f38605..c470613 100644
> --- a/xen/arch/arm/irq.c
> +++ b/xen/arch/arm/irq.c
> @@ -481,12 +481,23 @@ int route_irq_to_guest(struct domain *d, unsigned int 
> virq,
>           }
>
>           if ( test_bit(_IRQ_GUEST, &desc->status) )
> -            printk(XENLOG_G_ERR "IRQ %u is already used by domain %u\n",
> -                   irq, ad->domain_id);
> +        {
> +            printk(XENLOG_G_DEBUG "IRQ %u is reassigned from domain %u to domain 
> %u\n",
> +                    irq, ad->domain_id, d->domain_id);
> +
> +            retval = gic_remove_irq_from_guest(ad, irq, desc);
> +            if ( retval )
> +                printk(XENLOG_G_ERR "failed to remove IRQ %u from domain %u 
> (%d)\n",
> +                        irq, ad->domain_id, retval);
> +            xfree(desc->action);
> +            desc->action = NULL;
> +        }
>           else
> +        {
>               printk(XENLOG_G_ERR "IRQ %u is already used by Xen\n", irq);
> -        retval = -EBUSY;
> -        goto out;
> +                       retval = -EBUSY;
> +                       goto out;
> +        }
>       }
>
>       retval = __setup_irq(desc, 0, action);
--
Julien Grall

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